Condensation effects of indirect excitons in type II structures

Summary form only given. A system of indirect (interwell) excitons in coupled quantum wells (CQWs) provides a unique opportunity for experimental study of two-dimensional light composite bosons thermalized down to ultralow temperatures. The long recombination lifetime of indirect excitons promotes the exciton accumulation in the low energy exciton states and allows the system to cool down to temperatures where the exciton gas becomes degenerate at densities well below the Mott density. We present an experimental probe of the theoretically predicted specific bosonic properties of excitons such as stimulated exciton scattering due to high occupancy of exciton state and exciton Bose-Einstein condensation in GaAs/AlGaAs and AlAs/GaAs CQWs at ultralow temperatures T/sub bath/>50 mK.